Ctrl-D no longer works (Fedora 21, git-cola 2.1.2)

[WanWizard]

Problem is that https://github.com/git-cola/git-cola/blob/master/cola/cmds.py#L815 constructs an incorrect shell command.

It creates gnome-terminal -e git mergetool --no-prompt ... which fails with the error Failed to parse arguments: Unknown option --no-prompt because it sees the --no-prompt argument as part of gnome-terminal, and not of git.

The fixed xterm -e used in previous versions doesn't have this problem, which might be a reason why it hasn't been spotted before.